// Copyright (c) 2010. Eric Nelson  
// https://code.google.com/p/prompts/
// All rights reserved.
//     
// Redistribution and use in source and binary forms,   
// with or without modification, are permitted provided   
// that the following conditions are met:    
// * Redistributions of source code must retain the   
// above copyright notice, this list of conditions and   
// the following disclaimer.    
// * Redistributions in binary form must reproduce   
// the above copyright notice, this list of conditions   
// and the following disclaimer in the documentation   
// and/or other materials provided with the distribution.    
// * Neither the name of Eric Nelson nor the   
// names of its contributors may be used to endorse   
// or promote products derived from this software   
// without specific prior written permission.    
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND   
// CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,   
// INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF   
// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE   
// DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR   
// CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,   
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,   
// BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR   
// SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS   
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,   
// WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING   
// NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE   
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF   
// SUCH DAMAGE.
// 
//     
// [This is the BSD license, see  
// http://www.opensource.org/licenses/bsd-license.php]  
using System;
using System.Collections.Generic;
using Prompts.Prompting.Construction;
using Prompts.PromptServiceProxy;

namespace Prompts.Prompting.ViewModels.Implementation
{
    public class PromptsViewModelService : IPromptsViewModelService
    {
        private readonly IPromptsViewModelBuilder _promptsViewModelBuilder;
        private readonly IPromptServiceClient _promptService;
        private readonly Dictionary<string, Action<IEnumerable<IPrompt>>> _callbacks;

        public PromptsViewModelService(IPromptsViewModelBuilder promptsViewModelBuilder
            , IPromptServiceClient promptService)
        {
            _promptService = promptService;
            _promptsViewModelBuilder = promptsViewModelBuilder;
            _promptService.GetPromptsForReportCompleted += OnGetPromptsForReportCompleted;

            _callbacks = new Dictionary<string, Action<IEnumerable<IPrompt>>>();
        }

        public void GetPromptViewModels(string reportName, Action<IEnumerable<IPrompt>> result)
        {
            _callbacks.Add(reportName, result);
            _promptService.GetPromptsForReportAsync(reportName, reportName);
        }

        public void CancelGetPromptViewModels(string reportPath)
        {
            _callbacks.Remove(reportPath);
        }

        private void OnGetPromptsForReportCompleted(object sender, GetPromptsForReportCompletedEventArgs e)
        {
            var reportPath = (string)e.UserState;

            Action<IEnumerable<IPrompt>> callback;
            _callbacks.TryGetValue(reportPath, out callback);

            if(callback != null)
            {
                if (e.Result.ErrorOccured)
                {
                    var args = new ErrorGettingPromptsArgs(e.Result.ErrorMessage);
                    ErrorGettingPrompts(this, args);
                    return;
                }

                var promptCollection = _promptsViewModelBuilder.BuildFrom(reportPath, e.Result.Prompts);

                callback(promptCollection);
                _callbacks.Remove(reportPath);
            }
        }

        public delegate void ErrorGettingPromptsHandler(object sender, ErrorGettingPromptsArgs args);

        public event ErrorGettingPromptsHandler ErrorGettingPrompts;
    }
}